A BGP notification message is sent when an error condition is detected by the BGP process. The TCP connection with that BGP peer is closed after sending the notification message. Usually, the BGP process will log this notification in syslog, which would help us to identify the reason why the BGP session was brought down.
In this post, BGP notification message format along with error codes and subcodes are discussed. Continue reading
Below is a sample python code that can login to a switch via SSH and gather few command outputs and display it on console. SSH sessions are repeated for ‘x’ number of times.
Paramiko SSH module is used in this script. Paramiko is a native Python implementation of SSH. This module can be installed on a linux system using pip. commands are:
#sudo apt-get install python-pip
#sudo pip install paramiko
Code: Continue reading
Troubleshooting a network connectivity issue is quite challenging in a complex Data Center Network with live production traffic.
Below are few basic methods to identify a node in the traffic path that drops packets which would cause network connectivity issues. This procedure is in general and not related to any specific vendor as troubleshooting options varies with each vendor.
Let’s consider below simple topology for troubleshooting purpose:
R1(IP:22.214.171.124)— R2 — R3 — R4(IP:126.96.36.199)
Problem statement#1: 100% ping loss between R1 and R4. In this case, ping from R1 to R4’s interface IP fails 100%. Continue reading